/* * Copyright © 2012 Intel Corporation * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. */ /** * \file link_varyings.cpp * * Linker functions related specifically to linking varyings between shader * stages. */ #include "main/mtypes.h" #include "glsl_symbol_table.h" #include "glsl_parser_extras.h" #include "ir_optimization.h" #include "linker.h" #include "link_varyings.h" #include "main/macros.h" #include "program/hash_table.h" #include "program.h" /** * Get the varying type stripped of the outermost array if we're processing * a stage whose varyings are arrays indexed by a vertex number (such as * geometry shader inputs). */ static const glsl_type * get_varying_type(const ir_variable *var, gl_shader_stage stage) { const glsl_type *type = var->type; if (!var->data.patch && ((var->data.mode == ir_var_shader_out && stage == MESA_SHADER_TESS_CTRL) || (var->data.mode == ir_var_shader_in && (stage == MESA_SHADER_TESS_CTRL || stage == MESA_SHADER_TESS_EVAL || stage == MESA_SHADER_GEOMETRY)))) { assert(type->is_array()); type = type->fields.array; } return type; } static void create_xfb_varying_names(void *mem_ctx, const glsl_type *t, char **name, size_t name_length, unsigned *count, const char *ifc_member_name, const glsl_type *ifc_member_t, char ***varying_names) { if (t->is_interface()) { size_t new_length = name_length; assert(ifc_member_name && ifc_member_t); ralloc_asprintf_rewrite_tail(name, &new_length, ".%s", ifc_member_name); create_xfb_varying_names(mem_ctx, ifc_member_t, name, new_length, count, NULL, NULL, varying_names); } else if (t->is_record()) { for (unsigned i = 0; i < t->length; i++) { const char *field = t->fields.structure[i].name; size_t new_length = name_length; ralloc_asprintf_rewrite_tail(name, &new_length, ".%s", field); create_xfb_varying_names(mem_ctx, t->fields.structure[i].type, name, new_length, count, NULL, NULL, varying_names); } } else if (t->without_array()->is_record() || t->without_array()->is_interface() || (t->is_array() && t->fields.array->is_array())) { for (unsigned i = 0; i < t->length; i++) { size_t new_length = name_length; /* Append the subscript to the current variable name */ ralloc_asprintf_rewrite_tail(name, &new_length, "[%u]", i); create_xfb_varying_names(mem_ctx, t->fields.array, name, new_length, count, ifc_member_name, ifc_member_t, varying_names); } } else { (*varying_names)[(*count)++] = ralloc_strdup(mem_ctx, *name); } } bool process_xfb_layout_qualifiers(void *mem_ctx, const gl_shader *sh, unsigned *num_tfeedback_decls, char ***varying_names) { bool has_xfb_qualifiers = false; /* We still need to enable transform feedback mode even if xfb_stride is * only applied to a global out. Also we don't bother to propagate * xfb_stride to interface block members so this will catch that case also. */ for (unsigned j = 0; j < MAX_FEEDBACK_BUFFERS; j++) { if (sh->TransformFeedback.BufferStride[j]) { has_xfb_qualifiers = true; } } foreach_in_list(ir_instruction, node, sh->ir) { ir_variable *var = node->as_variable(); if (!var || var->data.mode != ir_var_shader_out) continue; /* From the ARB_enhanced_layouts spec: * * "Any shader making any static use (after preprocessing) of any of * these *xfb_* qualifiers will cause the shader to be in a * transform feedback capturing mode and hence responsible for * describing the transform feedback setup. This mode will capture * any output selected by *xfb_offset*, directly or indirectly, to * a transform feedback buffer." */ if (var->data.explicit_xfb_buffer || var->data.explicit_xfb_stride) { has_xfb_qualifiers = true; } if (var->data.explicit_xfb_offset) { *num_tfeedback_decls += var->type->varying_count(); has_xfb_qualifiers = true; } } if (*num_tfeedback_decls == 0) return has_xfb_qualifiers; unsigned i = 0; *varying_names = ralloc_array(mem_ctx, char *, *num_tfeedback_decls); foreach_in_list(ir_instruction, node, sh->ir) { ir_variable *var = node->as_variable(); if (!var || var->data.mode != ir_var_shader_out) continue; if (var->data.explicit_xfb_offset) { char *name; const glsl_type *type, *member_type; if (var->data.from_named_ifc_block) { type = var->get_interface_type(); /* Find the member type before it was altered by lowering */ member_type = type->fields.structure[type->field_index(var->name)].type; name = ralloc_strdup(NULL, type->without_array()->name); } else { type = var->type; member_type = NULL; name = ralloc_strdup(NULL, var->name); } create_xfb_varying_names(mem_ctx, type, &name, strlen(name), &i, var->name, member_type, varying_names); ralloc_free(name); } } assert(i == *num_tfeedback_decls); return has_xfb_qualifiers; } static bool anonymous_struct_type_matches(const glsl_type *output_type, const glsl_type *to_match) { while (output_type->is_array() && to_match->is_array()) { /* if the lengths at each level don't match fail. */ if (output_type->length != to_match->length) return false; output_type = output_type->fields.array; to_match = to_match->fields.array; } if (output_type->is_array() || to_match->is_array()) return false; return output_type->is_anonymous() && to_match->is_anonymous() && to_match->record_compare(output_type); } /** * Validate the types and qualifiers of an output from one stage against the * matching input to another stage. */ static void cross_validate_types_and_qualifiers(struct gl_shader_program *prog, const ir_variable *input, const ir_variable *output, gl_shader_stage consumer_stage, gl_shader_stage producer_stage) { /* Check that the types match between stages. */ const glsl_type *type_to_match = input->type; /* VS -> GS, VS -> TCS, VS -> TES, TES -> GS */ const bool extra_array_level = (producer_stage == MESA_SHADER_VERTEX && consumer_stage != MESA_SHADER_FRAGMENT) || consumer_stage == MESA_SHADER_GEOMETRY; if (extra_array_level) { assert(type_to_match->is_array()); type_to_match = type_to_match->fields.array; } if (type_to_match != output->type) { /* There is a bit of a special case for gl_TexCoord. This * built-in is unsized by default. Applications that variable * access it must redeclare it with a size. There is some * language in the GLSL spec that implies the fragment shader * and vertex shader do not have to agree on this size. Other * driver behave this way, and one or two applications seem to * rely on it. * * Neither declaration needs to be modified here because the array * sizes are fixed later when update_array_sizes is called. * * From page 48 (page 54 of the PDF) of the GLSL 1.10 spec: * * "Unlike user-defined varying variables, the built-in * varying variables don't have a strict one-to-one * correspondence between the vertex language and the * fragment language." */ if (!output->type->is_array() || !is_gl_identifier(output->name)) { bool anon_matches = anonymous_struct_type_matches(output->type, type_to_match); if (!anon_matches) { linker_error(prog, "%s shader output `%s' declared as type `%s', " "but %s shader input declared as type `%s'\n", _mesa_shader_stage_to_string(producer_stage), output->name, output->type->name, _mesa_shader_stage_to_string(consumer_stage), input->type->name); return; } } } /* Check that all of the qualifiers match between stages. */ /* According to the OpenGL and OpenGLES GLSL specs, the centroid qualifier * should match until OpenGL 4.3 and OpenGLES 3.1. The OpenGLES 3.0 * conformance test suite does not verify that the qualifiers must match. * The deqp test suite expects the opposite (OpenGLES 3.1) behavior for * OpenGLES 3.0 drivers, so we relax the checking in all cases. */ if (false /* always skip the centroid check */ && prog->Version < (prog->IsES ? 310 : 430) && input->data.centroid != output->data.centroid) { linker_error(prog, "%s shader output `%s' %s centroid qualifier, " "but %s shader input %s centroid qualifier\n", _mesa_shader_stage_to_string(producer_stage), output->name, (output->data.centroid) ? "has" : "lacks", _mesa_shader_stage_to_string(consumer_stage), (input->data.centroid) ? "has" : "lacks"); return; } if (input->data.sample != output->data.sample) { linker_error(prog, "%s shader output `%s' %s sample qualifier, " "but %s shader input %s sample qualifier\n", _mesa_shader_stage_to_string(producer_stage), output->name, (output->data.sample) ? "has" : "lacks", _mesa_shader_stage_to_string(consumer_stage), (input->data.sample) ? "has" : "lacks"); return; } if (input->data.patch != output->data.patch) { linker_error(prog, "%s shader output `%s' %s patch qualifier, " "but %s shader input %s patch qualifier\n", _mesa_shader_stage_to_string(producer_stage), output->name, (output->data.patch) ? "has" : "lacks", _mesa_shader_stage_to_string(consumer_stage), (input->data.patch) ? "has" : "lacks"); return; } /* The GLSL 4.30 and GLSL ES 3.00 specifications say: * * "As only outputs need be declared with invariant, an output from * one shader stage will still match an input of a subsequent stage * without the input being declared as invariant." * * while GLSL 4.20 says: * * "For variables leaving one shader and coming into another shader, * the invariant keyword has to be used in both shaders, or a link * error will result." * * and GLSL ES 1.00 section 4.6.4 "Invariance and Linking" says: * * "The invariance of varyings that are declared in both the vertex * and fragment shaders must match." */ if (input->data.invariant != output->data.invariant && prog->Version < (prog->IsES ? 300 : 430)) { linker_error(prog, "%s shader output `%s' %s invariant qualifier, " "but %s shader input %s invariant qualifier\n", _mesa_shader_stage_to_string(producer_stage), output->name, (output->data.invariant) ? "has" : "lacks", _mesa_shader_stage_to_string(consumer_stage), (input->data.invariant) ? "has" : "lacks"); return; } /* GLSL >= 4.40 removes text requiring interpolation qualifiers * to match cross stage, they must only match within the same stage. * * From page 84 (page 90 of the PDF) of the GLSL 4.40 spec: * * "It is a link-time error if, within the same stage, the interpolation * qualifiers of variables of the same name do not match. * */ if (input->data.interpolation != output->data.interpolation && prog->Version < 440) { linker_error(prog, "%s shader output `%s' specifies %s " "interpolation qualifier, " "but %s shader input specifies %s " "interpolation qualifier\n", _mesa_shader_stage_to_string(producer_stage), output->name, interpolation_string(output->data.interpolation), _mesa_shader_stage_to_string(consumer_stage), interpolation_string(input->data.interpolation)); return; } } /** * Validate front and back color outputs against single color input */ static void cross_validate_front_and_back_color(struct gl_shader_program *prog, const ir_variable *input, const ir_variable *front_color, const ir_variable *back_color, gl_shader_stage consumer_stage, gl_shader_stage producer_stage) { if (front_color != NULL && front_color->data.assigned) cross_validate_types_and_qualifiers(prog, input, front_color, consumer_stage, producer_stage); if (back_color != NULL && back_color->data.assigned) cross_validate_types_and_qualifiers(prog, input, back_color, consumer_stage, producer_stage); } /** * Validate that outputs from one stage match inputs of another */ void cross_validate_outputs_to_inputs(struct gl_shader_program *prog, gl_shader *producer, gl_shader *consumer) { glsl_symbol_table parameters; ir_variable *explicit_locations[MAX_VARYINGS_INCL_PATCH][4] = { {NULL, NULL} }; /* Find all shader outputs in the "producer" stage. */ foreach_in_list(ir_instruction, node, producer->ir) { ir_variable *const var = node->as_variable(); if (var == NULL || var->data.mode != ir_var_shader_out) continue; if (!var->data.explicit_location || var->data.location < VARYING_SLOT_VAR0) parameters.add_variable(var); else { /* User-defined varyings with explicit locations are handled * differently because they do not need to have matching names. */ const glsl_type *type = get_varying_type(var, producer->Stage); unsigned num_elements = type->count_attribute_slots(false); unsigned idx = var->data.location - VARYING_SLOT_VAR0; unsigned slot_limit = idx + num_elements; unsigned last_comp; if (var->type->without_array()->is_record()) { /* The component qualifier can't be used on structs so just treat * all component slots as used. */ last_comp = 4; } else { unsigned dmul = var->type->is_double() ? 2 : 1; last_comp = var->data.location_frac + var->type->without_array()->vector_elements * dmul; } while (idx < slot_limit) { unsigned i = var->data.location_frac; while (i < last_comp) { if (explicit_locations[idx][i] != NULL) { linker_error(prog, "%s shader has multiple outputs explicitly " "assigned to location %d and component %d\n", _mesa_shader_stage_to_string(producer->Stage), idx, var->data.location_frac); return; } /* Make sure all component at this location have the same type. */ for (unsigned j = 0; j < 4; j++) { if (explicit_locations[idx][j] && (explicit_locations[idx][j]->type->without_array() ->base_type != var->type->without_array()->base_type)) { linker_error(prog, "Varyings sharing the same location must " "have the same underlying numerical type. " "Location %u component %u\n", idx, var->data.location_frac); return; } } explicit_locations[idx][i] = var; i++; /* We need to do some special handling for doubles as dvec3 and * dvec4 consume two consecutive locations. We don't need to * worry about components beginning at anything other than 0 as * the spec does not allow this for dvec3 and dvec4. */ if (i == 3 && last_comp > 4) { last_comp = last_comp - 4; /* Bump location index and reset the component index */ idx++; i = 0; } } idx++; } } } /* Find all shader inputs in the "consumer" stage. Any variables that have * matching outputs already in the symbol table must have the same type and * qualifiers. * * Exception: if the consumer is the geometry shader, then the inputs * should be arrays and the type of the array element should match the type * of the corresponding producer output. */ foreach_in_list(ir_instruction, node, consumer->ir) { ir_variable *const input = node->as_variable(); if (input == NULL || input->data.mode != ir_var_shader_in) continue; if (strcmp(input->name, "gl_Color") == 0 && input->data.used) { const ir_variable *const front_color = parameters.get_variable("gl_FrontColor"); const ir_variable *const back_color = parameters.get_variable("gl_BackColor"); cross_validate_front_and_back_color(prog, input, front_color, back_color, consumer->Stage, producer->Stage); } else if (strcmp(input->name, "gl_SecondaryColor") == 0 && input->data.used) { const ir_variable *const front_color = parameters.get_variable("gl_FrontSecondaryColor"); const ir_variable *const back_color = parameters.get_variable("gl_BackSecondaryColor"); cross_validate_front_and_back_color(prog, input, front_color, back_color, consumer->Stage, producer->Stage); } else { /* The rules for connecting inputs and outputs change in the presence * of explicit locations. In this case, we no longer care about the * names of the variables. Instead, we care only about the * explicitly assigned location. */ ir_variable *output = NULL; if (input->data.explicit_location && input->data.location >= VARYING_SLOT_VAR0) { const glsl_type *type = get_varying_type(input, consumer->Stage); unsigned num_elements = type->count_attribute_slots(false); unsigned idx = input->data.location - VARYING_SLOT_VAR0; unsigned slot_limit = idx + num_elements; while (idx < slot_limit) { output = explicit_locations[idx][input->data.location_frac]; if (output == NULL || input->data.location != output->data.location) { linker_error(prog, "%s shader input `%s' with explicit location " "has no matching output\n", _mesa_shader_stage_to_string(consumer->Stage), input->name); break; } idx++; } } else { output = parameters.get_variable(input->name); } if (output != NULL) { /* Interface blocks have their own validation elsewhere so don't * try validating them here. */ if (!(input->get_interface_type() && output->get_interface_type())) cross_validate_types_and_qualifiers(prog, input, output, consumer->Stage, producer->Stage); } else { /* Check for input vars with unmatched output vars in prev stage * taking into account that interface blocks could have a matching * output but with different name, so we ignore them. */ assert(!input->data.assigned); if (input->data.used && !input->get_interface_type() && !input->data.explicit_location && !prog->SeparateShader) linker_error(prog, "%s shader input `%s' " "has no matching output in the previous stage\n", _mesa_shader_stage_to_string(consumer->Stage), input->name); } } } } /** * Demote shader inputs and outputs that are not used in other stages, and * remove them via dead code elimination. */ void remove_unused_shader_inputs_and_outputs(bool is_separate_shader_object, gl_shader *sh, enum ir_variable_mode mode) { if (is_separate_shader_object) return; foreach_in_list(ir_instruction, node, sh->ir) { ir_variable *const var = node->as_variable(); if (var == NULL || var->data.mode != int(mode)) continue; /* A shader 'in' or 'out' variable is only really an input or output if * its value is used by other shader stages. This will cause the * variable to have a location assigned. */ if (var->data.is_unmatched_generic_inout && !var->data.is_xfb_only) { assert(var->data.mode != ir_var_temporary); var->data.mode = ir_var_auto; } } /* Eliminate code that is now dead due to unused inputs/outputs being * demoted. */ while (do_dead_code(sh->ir, false)) ; } /** * Initialize this object based on a string that was passed to * glTransformFeedbackVaryings. * * If the input is mal-formed, this call still succeeds, but it sets * this->var_name to a mal-formed input, so tfeedback_decl::find_output_var() * will fail to find any matching variable. */ void tfeedback_decl::init(struct gl_context *ctx, const void *mem_ctx, const char *input) { /* We don't have to be pedantic about what is a valid GLSL variable name, * because any variable with an invalid name can't exist in the IR anyway. */ this->location = -1; this->orig_name = input; this->lowered_builtin_array_variable = none; this->skip_components = 0; this->next_buffer_separator = false; this->matched_candidate = NULL; this->stream_id = 0; this->buffer = 0; this->offset = 0; if (ctx->Extensions.ARB_transform_feedback3) { /* Parse gl_NextBuffer. */ if (strcmp(input, "gl_NextBuffer") == 0) { this->next_buffer_separator = true; return; } /* Parse gl_SkipComponents. */ if (strcmp(input, "gl_SkipComponents1") == 0) this->skip_components = 1; else if (strcmp(input, "gl_SkipComponents2") == 0) this->skip_components = 2; else if (strcmp(input, "gl_SkipComponents3") == 0) this->skip_components = 3; else if (strcmp(input, "gl_SkipComponents4") == 0) this->skip_components = 4; if (this->skip_components) return; } /* Parse a declaration. */ const char *base_name_end; long subscript = parse_program_resource_name(input, &base_name_end); this->var_name = ralloc_strndup(mem_ctx, input, base_name_end - input); if (this->var_name == NULL) { _mesa_error_no_memory(__func__); return; } if (subscript >= 0) { this->array_subscript = subscript; this->is_subscripted = true; } else { this->is_subscripted = false; } /* For drivers that lower gl_ClipDistance to gl_ClipDistanceMESA, this * class must behave specially to account for the fact that gl_ClipDistance * is converted from a float[8] to a vec4[2]. */ if (ctx->Const.ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerCombinedClipCullDistance && strcmp(this->var_name, "gl_ClipDistance") == 0) { this->lowered_builtin_array_variable = clip_distance; } if (ctx->Const.ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerCombinedClipCullDistance && strcmp(this->var_name, "gl_CullDistance") == 0) { this->lowered_builtin_array_variable = cull_distance; } if (ctx->Const.LowerTessLevel && (strcmp(this->var_name, "gl_TessLevelOuter") == 0)) this->lowered_builtin_array_variable = tess_level_outer; if (ctx->Const.LowerTessLevel && (strcmp(this->var_name, "gl_TessLevelInner") == 0)) this->lowered_builtin_array_variable = tess_level_inner; } /** * Determine whether two tfeedback_decl objects refer to the same variable and * array index (if applicable). */ bool tfeedback_decl::is_same(const tfeedback_decl &x, const tfeedback_decl &y) { assert(x.is_varying() && y.is_varying()); if (strcmp(x.var_name, y.var_name) != 0) return false; if (x.is_subscripted != y.is_subscripted) return false; if (x.is_subscripted && x.array_subscript != y.array_subscript) return false; return true; } /** * Assign a location and stream ID for this tfeedback_decl object based on the * transform feedback candidate found by find_candidate. * * If an error occurs, the error is reported through linker_error() and false * is returned. */ bool tfeedback_decl::assign_location(struct gl_context *ctx, struct gl_shader_program *prog) { assert(this->is_varying()); unsigned fine_location = this->matched_candidate->toplevel_var->data.location * 4 + this->matched_candidate->toplevel_var->data.location_frac + this->matched_candidate->offset; const unsigned dmul = this->matched_candidate->type->without_array()->is_double() ? 2 : 1; if (this->matched_candidate->type->is_array()) { /* Array variable */ const unsigned matrix_cols = this->matched_candidate->type->fields.array->matrix_columns; const unsigned vector_elements = this->matched_candidate->type->fields.array->vector_elements; unsigned actual_array_size; switch (this->lowered_builtin_array_variable) { case clip_distance: actual_array_size = prog->LastClipDistanceArraySize; break; case cull_distance: actual_array_size = prog->LastCullDistanceArraySize; break; case tess_level_outer: actual_array_size = 4; break; case tess_level_inner: actual_array_size = 2; break; case none: default: actual_array_size = this->matched_candidate->type->array_size(); break; } if (this->is_subscripted) { /* Check array bounds. */ if (this->array_subscript >= actual_array_size) { linker_error(prog, "Transform feedback varying %s has index " "%i, but the array size is %u.", this->orig_name, this->array_subscript, actual_array_size); return false; } unsigned array_elem_size = this->lowered_builtin_array_variable ? 1 : vector_elements * matrix_cols * dmul; fine_location += array_elem_size * this->array_subscript; this->size = 1; } else { this->size = actual_array_size; } this->vector_elements = vector_elements; this->matrix_columns = matrix_cols; if (this->lowered_builtin_array_variable) this->type = GL_FLOAT; else this->type = this->matched_candidate->type->fields.array->gl_type; } else { /* Regular variable (scalar, vector, or matrix) */ if (this->is_subscripted) { linker_error(prog, "Transform feedback varying %s requested, " "but %s is not an array.", this->orig_name, this->var_name); return false; } this->size = 1; this->vector_elements = this->matched_candidate->type->vector_elements; this->matrix_columns = this->matched_candidate->type->matrix_columns; this->type = this->matched_candidate->type->gl_type; } this->location = fine_location / 4; this->location_frac = fine_location % 4; /* From GL_EXT_transform_feedback: * A program will fail to link if: * * * the total number of components to capture in any varying * variable in is greater than the constant * MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS_EXT and the * buffer mode is SEPARATE_ATTRIBS_EXT; */ if (prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS && this->num_components() > ctx->Const.MaxTransformFeedbackSeparateComponents) { linker_error(prog, "Transform feedback varying %s exceeds " "MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS.", this->orig_name); return false; } /* Only transform feedback varyings can be assigned to non-zero streams, * so assign the stream id here. */ this->stream_id = this->matched_candidate->toplevel_var->data.stream; unsigned array_offset = this->array_subscript * 4 * dmul; unsigned struct_offset = this->matched_candidate->offset * 4 * dmul; this->buffer = this->matched_candidate->toplevel_var->data.xfb_buffer; this->offset = this->matched_candidate->toplevel_var->data.offset + array_offset + struct_offset; return true; } unsigned tfeedback_decl::get_num_outputs() const { if (!this->is_varying()) { return 0; } return (this->num_components() + this->location_frac + 3)/4; } /** * Update gl_transform_feedback_info to reflect this tfeedback_decl. * * If an error occurs, the error is reported through linker_error() and false * is returned. */ bool tfeedback_decl::store(struct gl_context *ctx, struct gl_shader_program *prog, struct gl_transform_feedback_info *info, unsigned buffer, unsigned buffer_index, const unsigned max_outputs, bool *explicit_stride, bool has_xfb_qualifiers) const { unsigned xfb_offset = 0; unsigned size = this->size; /* Handle gl_SkipComponents. */ if (this->skip_components) { info->Buffers[buffer].Stride += this->skip_components; size = this->skip_components; goto store_varying; } if (this->next_buffer_separator) { size = 0; goto store_varying; } if (has_xfb_qualifiers) { xfb_offset = this->offset / 4; } else { xfb_offset = info->Buffers[buffer].Stride; } info->Varyings[info->NumVarying].Offset = xfb_offset * 4; { unsigned location = this->location; unsigned location_frac = this->location_frac; unsigned num_components = this->num_components(); while (num_components > 0) { unsigned output_size = MIN2(num_components, 4 - location_frac); assert((info->NumOutputs == 0 && max_outputs == 0) || info->NumOutputs < max_outputs); /* From the ARB_enhanced_layouts spec: * * "If such a block member or variable is not written during a shader * invocation, the buffer contents at the assigned offset will be * undefined. Even if there are no static writes to a variable or * member that is assigned a transform feedback offset, the space is * still allocated in the buffer and still affects the stride." */ if (this->is_varying_written()) { info->Outputs[info->NumOutputs].ComponentOffset = location_frac; info->Outputs[info->NumOutputs].OutputRegister = location; info->Outputs[info->NumOutputs].NumComponents = output_size; info->Outputs[info->NumOutputs].StreamId = stream_id; info->Outputs[info->NumOutputs].OutputBuffer = buffer; info->Outputs[info->NumOutputs].DstOffset = xfb_offset; ++info->NumOutputs; } info->Buffers[buffer].Stream = this->stream_id; xfb_offset += output_size; num_components -= output_size; location++; location_frac = 0; } } if (explicit_stride && explicit_stride[buffer]) { if (this->is_double() && info->Buffers[buffer].Stride % 2) { linker_error(prog, "invalid qualifier xfb_stride=%d must be a " "multiple of 8 as its applied to a type that is or " "contains a double.", info->Buffers[buffer].Stride * 4); return false; } if ((this->offset / 4) / info->Buffers[buffer].Stride != (xfb_offset - 1) / info->Buffers[buffer].Stride) { linker_error(prog, "xfb_offset (%d) overflows xfb_stride (%d) for " "buffer (%d)", xfb_offset * 4, info->Buffers[buffer].Stride * 4, buffer); return false; } } else { info->Buffers[buffer].Stride = xfb_offset; } /* From GL_EXT_transform_feedback: * A program will fail to link if: * * * the total number of components to capture is greater than * the constant MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS_EXT * and the buffer mode is INTERLEAVED_ATTRIBS_EXT. * * From GL_ARB_enhanced_layouts: * * "The resulting stride (implicit or explicit) must be less than or * equal to the implementation-dependent constant * gl_MaxTransformFeedbackInterleavedComponents." */ if ((prog->TransformFeedback.BufferMode == GL_INTERLEAVED_ATTRIBS || has_xfb_qualifiers) && info->Buffers[buffer].Stride > ctx->Const.MaxTransformFeedbackInterleavedComponents) { linker_error(prog, "The MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS " "limit has been exceeded."); return false; } store_varying: info->Varyings[info->NumVarying].Name = ralloc_strdup(prog, this->orig_name); info->Varyings[info->NumVarying].Type = this->type; info->Varyings[info->NumVarying].Size = size; info->Varyings[info->NumVarying].BufferIndex = buffer_index; info->NumVarying++; info->Buffers[buffer].NumVaryings++; return true; } const tfeedback_candidate * tfeedback_decl::find_candidate(gl_shader_program *prog, hash_table *tfeedback_candidates) { const char *name = this->var_name; switch (this->lowered_builtin_array_variable) { case none: name = this->var_name; break; case clip_distance: name = "gl_ClipDistanceMESA"; break; case cull_distance: name = "gl_CullDistanceMESA"; break; case tess_level_outer: name = "gl_TessLevelOuterMESA"; break; case tess_level_inner: name = "gl_TessLevelInnerMESA"; break; } this->matched_candidate = (const tfeedback_candidate *) hash_table_find(tfeedback_candidates, name); if (!this->matched_candidate) { /* From GL_EXT_transform_feedback: * A program will fail to link if: * * * any variable name specified in the array is not * declared as an output in the geometry shader (if present) or * the vertex shader (if no geometry shader is present); */ linker_error(prog, "Transform feedback varying %s undeclared.", this->orig_name); } return this->matched_candidate; } /** * Parse all the transform feedback declarations that were passed to * glTransformFeedbackVaryings() and store them in tfeedback_decl objects. * * If an error occurs, the error is reported through linker_error() and false * is returned. */ bool parse_tfeedback_decls(struct gl_context *ctx, struct gl_shader_program *prog, const void *mem_ctx, unsigned num_names, char **varying_names, tfeedback_decl *decls) { for (unsigned i = 0; i < num_names; ++i) { decls[i].init(ctx, mem_ctx, varying_names[i]); if (!decls[i].is_varying()) continue; /* From GL_EXT_transform_feedback: * A program will fail to link if: * * * any two entries in the array specify the same varying * variable; * * We interpret this to mean "any two entries in the array * specify the same varying variable and array index", since transform * feedback of arrays would be useless otherwise. */ for (unsigned j = 0; j < i; ++j) { if (!decls[j].is_varying()) continue; if (tfeedback_decl::is_same(decls[i], decls[j])) { linker_error(prog, "Transform feedback varying %s specified " "more than once.", varying_names[i]); return false; } } } return true; } static int cmp_xfb_offset(const void * x_generic, const void * y_generic) { tfeedback_decl *x = (tfeedback_decl *) x_generic; tfeedback_decl *y = (tfeedback_decl *) y_generic; if (x->get_buffer() != y->get_buffer()) return x->get_buffer() - y->get_buffer(); return x->get_offset() - y->get_offset(); } /** * Store transform feedback location assignments into * prog->LinkedTransformFeedback based on the data stored in tfeedback_decls. * * If an error occurs, the error is reported through linker_error() and false * is returned. */ bool store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog, unsigned num_tfeedback_decls, tfeedback_decl *tfeedback_decls, bool has_xfb_qualifiers) { /* Make sure MaxTransformFeedbackBuffers is less than 32 so the bitmask for * tracking the number of buffers doesn't overflow. */ assert(ctx->Const.MaxTransformFeedbackBuffers < 32); bool separate_attribs_mode = prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS; ralloc_free(prog->LinkedTransformFeedback.Varyings); ralloc_free(prog->LinkedTransformFeedback.Outputs); memset(&prog->LinkedTransformFeedback, 0, sizeof(prog->LinkedTransformFeedback)); /* The xfb_offset qualifier does not have to be used in increasing order * however some drivers expect to receive the list of transform feedback * declarations in order so sort it now for convenience. */ if (has_xfb_qualifiers) qsort(tfeedback_decls, num_tfeedback_decls, sizeof(*tfeedback_decls), cmp_xfb_offset); prog->LinkedTransformFeedback.Varyings = rzalloc_array(prog, struct gl_transform_feedback_varying_info, num_tfeedback_decls); unsigned num_outputs = 0; for (unsigned i = 0; i < num_tfeedback_decls; ++i) { if (tfeedback_decls[i].is_varying_written()) num_outputs += tfeedback_decls[i].get_num_outputs(); } prog->LinkedTransformFeedback.Outputs = rzalloc_array(prog, struct gl_transform_feedback_output, num_outputs); unsigned num_buffers = 0; unsigned buffers = 0; if (!has_xfb_qualifiers && separate_attribs_mode) { /* GL_SEPARATE_ATTRIBS */ for (unsigned i = 0; i < num_tfeedback_decls; ++i) { if (!tfeedback_decls[i].store(ctx, prog, &prog->LinkedTransformFeedback, num_buffers, num_buffers, num_outputs, NULL, has_xfb_qualifiers)) return false; buffers |= 1 << num_buffers; num_buffers++; } } else { /* GL_INVERLEAVED_ATTRIBS */ int buffer_stream_id = -1; unsigned buffer = num_tfeedback_decls ? tfeedback_decls[0].get_buffer() : 0; bool explicit_stride[MAX_FEEDBACK_BUFFERS] = { false }; /* Apply any xfb_stride global qualifiers */ if (has_xfb_qualifiers) { for (unsigned j = 0; j < MAX_FEEDBACK_BUFFERS; j++) { if (prog->TransformFeedback.BufferStride[j]) { buffers |= 1 << j; explicit_stride[j] = true; prog->LinkedTransformFeedback.Buffers[j].Stride = prog->TransformFeedback.BufferStride[j] / 4; } } } for (unsigned i = 0; i < num_tfeedback_decls; ++i) { if (has_xfb_qualifiers && buffer != tfeedback_decls[i].get_buffer()) { /* we have moved to the next buffer so reset stream id */ buffer_stream_id = -1; num_buffers++; } if (tfeedback_decls[i].is_next_buffer_separator()) { if (!tfeedback_decls[i].store(ctx, prog, &prog->LinkedTransformFeedback, buffer, num_buffers, num_outputs, explicit_stride, has_xfb_qualifiers)) return false; num_buffers++; buffer_stream_id = -1; continue; } else if (tfeedback_decls[i].is_varying()) { if (buffer_stream_id == -1) { /* First varying writing to this buffer: remember its stream */ buffer_stream_id = (int) tfeedback_decls[i].get_stream_id(); } else if (buffer_stream_id != (int) tfeedback_decls[i].get_stream_id()) { /* Varying writes to the same buffer from a different stream */ linker_error(prog, "Transform feedback can't capture varyings belonging " "to different vertex streams in a single buffer. " "Varying %s writes to buffer from stream %u, other " "varyings in the same buffer write from stream %u.", tfeedback_decls[i].name(), tfeedback_decls[i].get_stream_id(), buffer_stream_id); return false; } } if (has_xfb_qualifiers) { buffer = tfeedback_decls[i].get_buffer(); } else { buffer = num_buffers; } buffers |= 1 << buffer; if (!tfeedback_decls[i].store(ctx, prog, &prog->LinkedTransformFeedback, buffer, num_buffers, num_outputs, explicit_stride, has_xfb_qualifiers)) return false; } } assert(prog->LinkedTransformFeedback.NumOutputs == num_outputs); prog->LinkedTransformFeedback.ActiveBuffers = buffers; return true; } namespace { /** * Data structure recording the relationship between outputs of one shader * stage (the "producer") and inputs of another (the "consumer"). */ class varying_matches { public: varying_matches(bool disable_varying_packing, bool xfb_enabled, gl_shader_stage producer_stage, gl_shader_stage consumer_stage); ~varying_matches(); void record(ir_variable *producer_var, ir_variable *consumer_var); unsigned assign_locations(struct gl_shader_program *prog, uint64_t reserved_slots); void store_locations() const; private: bool is_varying_packing_safe(const glsl_type *type, const ir_variable *var); /** * If true, this driver disables varying packing, so all varyings need to * be aligned on slot boundaries, and take up a number of slots equal to * their number of matrix columns times their array size. * * Packing may also be disabled because our current packing method is not * safe in SSO or versions of OpenGL where interpolation qualifiers are not * guaranteed to match across stages. */ const bool disable_varying_packing; /** * If true, this driver has transform feedback enabled. The transform * feedback code requires at least some packing be done even when varying * packing is disabled, fortunately where transform feedback requires * packing it's safe to override the disabled setting. See * is_varying_packing_safe(). */ const bool xfb_enabled; /** * Enum representing the order in which varyings are packed within a * packing class. * * Currently we pack vec4's first, then vec2's, then scalar values, then * vec3's. This order ensures that the only vectors that are at risk of * having to be "double parked" (split between two adjacent varying slots) * are the vec3's. */ enum packing_order_enum { PACKING_ORDER_VEC4, PACKING_ORDER_VEC2, PACKING_ORDER_SCALAR, PACKING_ORDER_VEC3, }; static unsigned compute_packing_class(const ir_variable *var); static packing_order_enum compute_packing_order(const ir_variable *var); static int match_comparator(const void *x_generic, const void *y_generic); static int xfb_comparator(const void *x_generic, const void *y_generic); /** * Structure recording the relationship between a single producer output * and a single consumer input. */ struct match { /** * Packing class for this varying, computed by compute_packing_class(). */ unsigned packing_class; /** * Packing order for this varying, computed by compute_packing_order(). */ packing_order_enum packing_order; unsigned num_components; /** * The output variable in the producer stage. */ ir_variable *producer_var; /** * The input variable in the consumer stage. */ ir_variable *consumer_var; /** * The location which has been assigned for this varying. This is * expressed in multiples of a float, with the first generic varying * (i.e. the one referred to by VARYING_SLOT_VAR0) represented by the * value 0. */ unsigned generic_location; } *matches; /** * The number of elements in the \c matches array that are currently in * use. */ unsigned num_matches; /** * The number of elements that were set aside for the \c matches array when * it was allocated. */ unsigned matches_capacity; gl_shader_stage producer_stage; gl_shader_stage consumer_stage; }; } /* anonymous namespace */ varying_matches::varying_matches(bool disable_varying_packing, bool xfb_enabled, gl_shader_stage producer_stage, gl_shader_stage consumer_stage) : disable_varying_packing(disable_varying_packing), xfb_enabled(xfb_enabled), producer_stage(producer_stage), consumer_stage(consumer_stage) { /* Note: this initial capacity is rather arbitrarily chosen to be large * enough for many cases without wasting an unreasonable amount of space. * varying_matches::record() will resize the array if there are more than * this number of varyings. */ this->matches_capacity = 8; this->matches = (match *) malloc(sizeof(*this->matches) * this->matches_capacity); this->num_matches = 0; } varying_matches::~varying_matches() { free(this->matches); } /** * Packing is always safe on individual arrays, structures, and matrices. It * is also safe if the varying is only used for transform feedback. */ bool varying_matches::is_varying_packing_safe(const glsl_type *type, const ir_variable *var) { if (consumer_stage == MESA_SHADER_TESS_EVAL || consumer_stage == MESA_SHADER_TESS_CTRL || producer_stage == MESA_SHADER_TESS_CTRL) return false; return xfb_enabled && (type->is_array() || type->is_record() || type->is_matrix() || var->data.is_xfb_only); } /** * Record the given producer/consumer variable pair in the list of variables * that should later be assigned locations. * * It is permissible for \c consumer_var to be NULL (this happens if a * variable is output by the producer and consumed by transform feedback, but * not consumed by the consumer). * * If \c producer_var has already been paired up with a consumer_var, or * producer_var is part of fixed pipeline functionality (and hence already has * a location assigned), this function has no effect. * * Note: as a side effect this function may change the interpolation type of * \c producer_var, but only when the change couldn't possibly affect * rendering. */ void varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var) { assert(producer_var != NULL || consumer_var != NULL); if ((producer_var && (!producer_var->data.is_unmatched_generic_inout || producer_var->data.explicit_location)) || (consumer_var && (!consumer_var->data.is_unmatched_generic_inout || consumer_var->data.explicit_location))) { /* Either a location already exists for this variable (since it is part * of fixed functionality), or it has already been recorded as part of a * previous match. */ return; } bool needs_flat_qualifier = consumer_var == NULL && (producer_var->type->contains_integer() || producer_var->type->contains_double()); if (needs_flat_qualifier || (consumer_stage != -1 && consumer_stage != MESA_SHADER_FRAGMENT)) { /* Since this varying is not being consumed by the fragment shader, its * interpolation type varying cannot possibly affect rendering. * Also, this variable is non-flat and is (or contains) an integer * or a double. * If the consumer stage is unknown, don't modify the interpolation * type as it could affect rendering later with separate shaders. * * lower_packed_varyings requires all integer varyings to flat, * regardless of where they appear. We can trivially satisfy that * requirement by changing the interpolation type to flat here. */ if (producer_var) { producer_var->data.centroid = false; producer_var->data.sample = false; producer_var->data.interpolation = INTERP_QUALIFIER_FLAT; } if (consumer_var) { consumer_var->data.centroid = false; consumer_var->data.sample = false; consumer_var->data.interpolation = INTERP_QUALIFIER_FLAT; } } if (this->num_matches == this->matches_capacity) { this->matches_capacity *= 2; this->matches = (match *) realloc(this->matches, sizeof(*this->matches) * this->matches_capacity); } const ir_variable *const var = (producer_var != NULL) ? producer_var : consumer_var; const gl_shader_stage stage = (producer_var != NULL) ? producer_stage : consumer_stage; const glsl_type *type = get_varying_type(var, stage); this->matches[this->num_matches].packing_class = this->compute_packing_class(var); this->matches[this->num_matches].packing_order = this->compute_packing_order(var); if (this->disable_varying_packing && !is_varying_packing_safe(type, var)) { unsigned slots = type->count_attribute_slots(false); this->matches[this->num_matches].num_components = slots * 4; } else { this->matches[this->num_matches].num_components = type->component_slots(); } this->matches[this->num_matches].producer_var = producer_var; this->matches[this->num_matches].consumer_var = consumer_var; this->num_matches++; if (producer_var) producer_var->data.is_unmatched_generic_inout = 0; if (consumer_var) consumer_var->data.is_unmatched_generic_inout = 0; } /** * Choose locations for all of the variable matches that were previously * passed to varying_matches::record(). */ unsigned varying_matches::assign_locations(struct gl_shader_program *prog, uint64_t reserved_slots) { /* If packing has been disabled then we cannot safely sort the varyings by * class as it may mean we are using a version of OpenGL where * interpolation qualifiers are not guaranteed to be matching across * shaders, sorting in this case could result in mismatching shader * interfaces. * When packing is disabled the sort orders varyings used by transform * feedback first, but also depends on *undefined behaviour* of qsort to * reverse the order of the varyings. See: xfb_comparator(). */ if (!this->disable_varying_packing) { /* Sort varying matches into an order that makes them easy to pack. */ qsort(this->matches, this->num_matches, sizeof(*this->matches), &varying_matches::match_comparator); } else { /* Only sort varyings that are only used by transform feedback. */ qsort(this->matches, this->num_matches, sizeof(*this->matches), &varying_matches::xfb_comparator); } unsigned generic_location = 0; unsigned generic_patch_location = MAX_VARYING*4; bool previous_var_xfb_only = false; for (unsigned i = 0; i < this->num_matches; i++) { unsigned *location = &generic_location; const ir_variable *var; const glsl_type *type; bool is_vertex_input = false; if (matches[i].consumer_var) { var = matches[i].consumer_var; type = get_varying_type(var, consumer_stage); if (consumer_stage == MESA_SHADER_VERTEX) is_vertex_input = true; } else { var = matches[i].producer_var; type = get_varying_type(var, producer_stage); } if (var->data.patch) location = &generic_patch_location; /* Advance to the next slot if this varying has a different packing * class than the previous one, and we're not already on a slot * boundary. * * Also advance to the next slot if packing is disabled. This makes sure * we don't assign varyings the same locations which is possible * because we still pack individual arrays, records and matrices even * when packing is disabled. Note we don't advance to the next slot if * we can pack varyings together that are only used for transform * feedback. */ if ((this->disable_varying_packing && !(previous_var_xfb_only && var->data.is_xfb_only)) || (i > 0 && this->matches[i - 1].packing_class != this->matches[i].packing_class )) { *location = ALIGN(*location, 4); } previous_var_xfb_only = var->data.is_xfb_only; unsigned num_elements = type->count_attribute_slots(is_vertex_input); unsigned slot_end; if (this->disable_varying_packing && !is_varying_packing_safe(type, var)) slot_end = 4; else slot_end = type->without_array()->vector_elements; slot_end += *location - 1; /* FIXME: We could be smarter in the below code and loop back over * trying to fill any locations that we skipped because we couldn't pack * the varying between an explicit location. For now just let the user * hit the linking error if we run out of room and suggest they use * explicit locations. */ for (unsigned j = 0; j < num_elements; j++) { while ((slot_end < MAX_VARYING * 4u) && ((reserved_slots & (UINT64_C(1) << *location / 4u) || (reserved_slots & (UINT64_C(1) << slot_end / 4u))))) { *location = ALIGN(*location + 1, 4); slot_end = *location; /* reset the counter and try again */ j = 0; } /* Increase the slot to make sure there is enough room for next * array element. */ if (this->disable_varying_packing && !is_varying_packing_safe(type, var)) slot_end += 4; else slot_end += type->without_array()->vector_elements; } if (!var->data.patch && *location >= MAX_VARYING * 4u) { linker_error(prog, "insufficient contiguous locations available for " "%s it is possible an array or struct could not be " "packed between varyings with explicit locations. Try " "using an explicit location for arrays and structs.", var->name); } this->matches[i].generic_location = *location; *location += this->matches[i].num_components; } return (generic_location + 3) / 4; } /** * Update the producer and consumer shaders to reflect the locations * assignments that were made by varying_matches::assign_locations(). */ void varying_matches::store_locations() const { for (unsigned i = 0; i < this->num_matches; i++) { ir_variable *producer_var = this->matches[i].producer_var; ir_variable *consumer_var = this->matches[i].consumer_var; unsigned generic_location = this->matches[i].generic_location; unsigned slot = generic_location / 4; unsigned offset = generic_location % 4; if (producer_var) { producer_var->data.location = VARYING_SLOT_VAR0 + slot; producer_var->data.location_frac = offset; } if (consumer_var) { assert(consumer_var->data.location == -1); consumer_var->data.location = VARYING_SLOT_VAR0 + slot; consumer_var->data.location_frac = offset; } } } /** * Compute the "packing class" of the given varying. This is an unsigned * integer with the property that two variables in the same packing class can * be safely backed into the same vec4. */ unsigned varying_matches::compute_packing_class(const ir_variable *var) { /* Without help from the back-end, there is no way to pack together * variables with different interpolation types, because * lower_packed_varyings must choose exactly one interpolation type for * each packed varying it creates. * * However, we can safely pack together floats, ints, and uints, because: * * - varyings of base type "int" and "uint" must use the "flat" * interpolation type, which can only occur in GLSL 1.30 and above. * * - On platforms that support GLSL 1.30 and above, lower_packed_varyings * can store flat floats as ints without losing any information (using * the ir_unop_bitcast_* opcodes). * * Therefore, the packing class depends only on the interpolation type. */ unsigned packing_class = var->data.centroid | (var->data.sample << 1) | (var->data.patch << 2); packing_class *= 4; packing_class += var->is_interpolation_flat() ? unsigned(INTERP_QUALIFIER_FLAT) : var->data.interpolation; return packing_class; } /** * Compute the "packing order" of the given varying. This is a sort key we * use to determine when to attempt to pack the given varying relative to * other varyings in the same packing class. */ varying_matches::packing_order_enum varying_matches::compute_packing_order(const ir_variable *var) { const glsl_type *element_type = var->type; while (element_type->base_type == GLSL_TYPE_ARRAY) { element_type = element_type->fields.array; } switch (element_type->component_slots() % 4) { case 1: return PACKING_ORDER_SCALAR; case 2: return PACKING_ORDER_VEC2; case 3: return PACKING_ORDER_VEC3; case 0: return PACKING_ORDER_VEC4; default: assert(!"Unexpected value of vector_elements"); return PACKING_ORDER_VEC4; } } /** * Comparison function passed to qsort() to sort varyings by packing_class and * then by packing_order. */ int varying_matches::match_comparator(const void *x_generic, const void *y_generic) { const match *x = (const match *) x_generic; const match *y = (const match *) y_generic; if (x->packing_class != y->packing_class) return x->packing_class - y->packing_class; return x->packing_order - y->packing_order; } /** * Comparison function passed to qsort() to sort varyings used only by * transform feedback when packing of other varyings is disabled. */ int varying_matches::xfb_comparator(const void *x_generic, const void *y_generic) { const match *x = (const match *) x_generic; if (x->producer_var != NULL && x->producer_var->data.is_xfb_only) return match_comparator(x_generic, y_generic); /* FIXME: When the comparator returns 0 it means the elements being * compared are equivalent. However the qsort documentation says: * * "The order of equivalent elements is undefined." * * In practice the sort ends up reversing the order of the varyings which * means locations are also assigned in this reversed order and happens to * be what we want. This is also whats happening in * varying_matches::match_comparator(). */ return 0; } /** * Is the given variable a varying variable to be counted against the * limit in ctx->Const.MaxVarying? * This includes variables such as texcoords, colors and generic * varyings, but excludes variables such as gl_FrontFacing and gl_FragCoord. */ static bool var_counts_against_varying_limit(gl_shader_stage stage, const ir_variable *var) { /* Only fragment shaders will take a varying variable as an input */ if (stage == MESA_SHADER_FRAGMENT && var->data.mode == ir_var_shader_in) { switch (var->data.location) { case VARYING_SLOT_POS: case VARYING_SLOT_FACE: case VARYING_SLOT_PNTC: return false; default: return true; } } return false; } /** * Visitor class that generates tfeedback_candidate structs describing all * possible targets of transform feedback. * * tfeedback_candidate structs are stored in the hash table * tfeedback_candidates, which is passed to the constructor. This hash table * maps varying names to instances of the tfeedback_candidate struct. */ class tfeedback_candidate_generator : public program_resource_visitor { public: tfeedback_candidate_generator(void *mem_ctx, hash_table *tfeedback_candidates) : mem_ctx(mem_ctx), tfeedback_candidates(tfeedback_candidates), toplevel_var(NULL), varying_floats(0) { } void process(ir_variable *var) { /* All named varying interface blocks should be flattened by now */ assert(!var->is_interface_instance()); this->toplevel_var = var; this->varying_floats = 0; program_resource_visitor::process(var); } private: virtual void visit_field(const glsl_type *type, const char *name, bool row_major) { assert(!type->without_array()->is_record()); assert(!type->without_array()->is_interface()); (void) row_major; tfeedback_candidate *candidate = rzalloc(this->mem_ctx, tfeedback_candidate); candidate->toplevel_var = this->toplevel_var; candidate->type = type; candidate->offset = this->varying_floats; hash_table_insert(this->tfeedback_candidates, candidate, ralloc_strdup(this->mem_ctx, name)); this->varying_floats += type->component_slots(); } /** * Memory context used to allocate hash table keys and values. */ void * const mem_ctx; /** * Hash table in which tfeedback_candidate objects should be stored. */ hash_table * const tfeedback_candidates; /** * Pointer to the toplevel variable that is being traversed. */ ir_variable *toplevel_var; /** * Total number of varying floats that have been visited so far. This is * used to determine the offset to each varying within the toplevel * variable. */ unsigned varying_floats; }; namespace linker { void populate_consumer_input_sets(void *mem_ctx, exec_list *ir, hash_table *consumer_inputs, hash_table *consumer_interface_inputs, ir_variable *consumer_inputs_with_locations[VARYING_SLOT_TESS_MAX]) { memset(consumer_inputs_with_locations, 0, sizeof(consumer_inputs_with_locations[0]) * VARYING_SLOT_TESS_MAX); foreach_in_list(ir_instruction, node, ir) { ir_variable *const input_var = node->as_variable(); if (input_var != NULL && input_var->data.mode == ir_var_shader_in) { /* All interface blocks should have been lowered by this point */ assert(!input_var->type->is_interface()); if (input_var->data.explicit_location) { /* assign_varying_locations only cares about finding the * ir_variable at the start of a contiguous location block. * * - For !producer, consumer_inputs_with_locations isn't used. * * - For !consumer, consumer_inputs_with_locations is empty. * * For consumer && producer, if you were trying to set some * ir_variable to the middle of a location block on the other side * of producer/consumer, cross_validate_outputs_to_inputs() should * be link-erroring due to either type mismatch or location * overlaps. If the variables do match up, then they've got a * matching data.location and you only looked at * consumer_inputs_with_locations[var->data.location], not any * following entries for the array/structure. */ consumer_inputs_with_locations[input_var->data.location] = input_var; } else if (input_var->get_interface_type() != NULL) { char *const iface_field_name = ralloc_asprintf(mem_ctx, "%s.%s", input_var->get_interface_type()->without_array()->name, input_var->name); hash_table_insert(consumer_interface_inputs, input_var, iface_field_name); } else { hash_table_insert(consumer_inputs, input_var, ralloc_strdup(mem_ctx, input_var->name)); } } } } /** * Find a variable from the consumer that "matches" the specified variable * * This function only finds inputs with names that match. There is no * validation (here) that the types, etc. are compatible. */ ir_variable * get_matching_input(void *mem_ctx, const ir_variable *output_var, hash_table *consumer_inputs, hash_table *consumer_interface_inputs, ir_variable *consumer_inputs_with_locations[VARYING_SLOT_TESS_MAX]) { ir_variable *input_var; if (output_var->data.explicit_location) { input_var = consumer_inputs_with_locations[output_var->data.location]; } else if (output_var->get_interface_type() != NULL) { char *const iface_field_name = ralloc_asprintf(mem_ctx, "%s.%s", output_var->get_interface_type()->without_array()->name, output_var->name); input_var = (ir_variable *) hash_table_find(consumer_interface_inputs, iface_field_name); } else { input_var = (ir_variable *) hash_table_find(consumer_inputs, output_var->name); } return (input_var == NULL || input_var->data.mode != ir_var_shader_in) ? NULL : input_var; } } static int io_variable_cmp(const void *_a, const void *_b) { const ir_variable *const a = *(const ir_variable **) _a; const ir_variable *const b = *(const ir_variable **) _b; if (a->data.explicit_location && b->data.explicit_location) return b->data.location - a->data.location; if (a->data.explicit_location && !b->data.explicit_location) return 1; if (!a->data.explicit_location && b->data.explicit_location) return -1; return -strcmp(a->name, b->name); } /** * Sort the shader IO variables into canonical order */ static void canonicalize_shader_io(exec_list *ir, enum ir_variable_mode io_mode) { ir_variable *var_table[MAX_PROGRAM_OUTPUTS * 4]; unsigned num_variables = 0; foreach_in_list(ir_instruction, node, ir) { ir_variable *const var = node->as_variable(); if (var == NULL || var->data.mode != io_mode) continue; /* If we have already encountered more I/O variables that could * successfully link, bail. */ if (num_variables == ARRAY_SIZE(var_table)) return; var_table[num_variables++] = var; } if (num_variables == 0) return; /* Sort the list in reverse order (io_variable_cmp handles this). Later * we're going to push the variables on to the IR list as a stack, so we * want the last variable (in canonical order) to be first in the list. */ qsort(var_table, num_variables, sizeof(var_table[0]), io_variable_cmp); /* Remove the variable from it's current location in the IR, and put it at * the front. */ for (unsigned i = 0; i < num_variables; i++) { var_table[i]->remove(); ir->push_head(var_table[i]); } } /** * Generate a bitfield map of the explicit locations for shader varyings. * * Note: For Tessellation shaders we are sitting right on the limits of the * 64 bit map. Per-vertex and per-patch both have separate location domains * with a max of MAX_VARYING. */ static uint64_t reserved_varying_slot(struct gl_shader *stage, ir_variable_mode io_mode) { assert(io_mode == ir_var_shader_in || io_mode == ir_var_shader_out); /* Avoid an overflow of the returned value */ assert(MAX_VARYINGS_INCL_PATCH <= 64); uint64_t slots = 0; int var_slot; if (!stage) return slots; foreach_in_list(ir_instruction, node, stage->ir) { ir_variable *const var = node->as_variable(); if (var == NULL || var->data.mode != io_mode || !var->data.explicit_location || var->data.location < VARYING_SLOT_VAR0) continue; var_slot = var->data.location - VARYING_SLOT_VAR0; unsigned num_elements = get_varying_type(var, stage->Stage) ->count_attribute_slots(stage->Stage == MESA_SHADER_VERTEX); for (unsigned i = 0; i < num_elements; i++) { if (var_slot >= 0 && var_slot < MAX_VARYINGS_INCL_PATCH) slots |= UINT64_C(1) << var_slot; var_slot += 1; } } return slots; } /** * Assign locations for all variables that are produced in one pipeline stage * (the "producer") and consumed in the next stage (the "consumer"). * * Variables produced by the producer may also be consumed by transform * feedback. * * \param num_tfeedback_decls is the number of declarations indicating * variables that may be consumed by transform feedback. * * \param tfeedback_decls is a pointer to an array of tfeedback_decl objects * representing the result of parsing the strings passed to * glTransformFeedbackVaryings(). assign_location() will be called for * each of these objects that matches one of the outputs of the * producer. * * When num_tfeedback_decls is nonzero, it is permissible for the consumer to * be NULL. In this case, varying locations are assigned solely based on the * requirements of transform feedback. */ bool assign_varying_locations(struct gl_context *ctx, void *mem_ctx, struct gl_shader_program *prog, gl_shader *producer, gl_shader *consumer, unsigned num_tfeedback_decls, tfeedback_decl *tfeedback_decls) { /* Tessellation shaders treat inputs and outputs as shared memory and can * access inputs and outputs of other invocations. * Therefore, they can't be lowered to temps easily (and definitely not * efficiently). */ bool unpackable_tess = (consumer && consumer->Stage == MESA_SHADER_TESS_EVAL) || (consumer && consumer->Stage == MESA_SHADER_TESS_CTRL) || (producer && producer->Stage == MESA_SHADER_TESS_CTRL); /* Transform feedback code assumes varying arrays are packed, so if the * driver has disabled varying packing, make sure to at least enable * packing required by transform feedback. */ bool xfb_enabled = ctx->Extensions.EXT_transform_feedback && !unpackable_tess; /* Disable varying packing for GL 4.4+ as there is no guarantee * that interpolation qualifiers will match between shaders in these * versions. We also disable packing on outward facing interfaces for * SSO because in ES we need to retain the unpacked varying information * for draw time validation. For desktop GL we could allow packing for * versions < 4.4 but it's just safer not to do packing. * * Packing is still enabled on individual arrays, structs, and matrices as * these are required by the transform feedback code and it is still safe * to do so. We also enable packing when a varying is only used for * transform feedback and its not a SSO. * * Varying packing currently only packs together varyings with matching * interpolation qualifiers as the backends assume all packed components * are to be processed in the same way. Therefore we cannot do packing in * these versions of GL without the risk of mismatching interfaces. * * From Section 4.5 (Interpolation Qualifiers) of the GLSL 4.30 spec: * * "The type and presence of interpolation qualifiers of variables with * the same name declared in all linked shaders for the same cross-stage * interface must match, otherwise the link command will fail. * * When comparing an output from one stage to an input of a subsequent * stage, the input and output don't match if their interpolation * qualifiers (or lack thereof) are not the same." * * This text was also in at least revison 7 of the 4.40 spec but is no * longer in revision 9 and not in the 4.50 spec. */ bool disable_varying_packing = ctx->Const.DisableVaryingPacking || unpackable_tess; if ((ctx->API == API_OPENGL_CORE && ctx->Version >= 44) || (prog->SeparateShader && (producer == NULL || consumer == NULL))) disable_varying_packing = true; varying_matches matches(disable_varying_packing, xfb_enabled, producer ? producer->Stage : (gl_shader_stage)-1, consumer ? consumer->Stage : (gl_shader_stage)-1); hash_table *tfeedback_candidates = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare); hash_table *consumer_inputs = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare); hash_table *consumer_interface_inputs = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare); ir_variable *consumer_inputs_with_locations[VARYING_SLOT_TESS_MAX] = { NULL, }; unsigned consumer_vertices = 0; if (consumer && consumer->Stage == MESA_SHADER_GEOMETRY) consumer_vertices = prog->Geom.VerticesIn; /* Operate in a total of four passes. * * 1. Sort inputs / outputs into a canonical order. This is necessary so * that inputs / outputs of separable shaders will be assigned * predictable locations regardless of the order in which declarations * appeared in the shader source. * * 2. Assign locations for any matching inputs and outputs. * * 3. Mark output variables in the producer that do not have locations as * not being outputs. This lets the optimizer eliminate them. * * 4. Mark input variables in the consumer that do not have locations as * not being inputs. This lets the optimizer eliminate them. */ if (consumer) canonicalize_shader_io(consumer->ir, ir_var_shader_in); if (producer) canonicalize_shader_io(producer->ir, ir_var_shader_out); if (consumer) linker::populate_consumer_input_sets(mem_ctx, consumer->ir, consumer_inputs, consumer_interface_inputs, consumer_inputs_with_locations); if (producer) { foreach_in_list(ir_instruction, node, producer->ir) { ir_variable *const output_var = node->as_variable(); if (output_var == NULL || output_var->data.mode != ir_var_shader_out) continue; /* Only geometry shaders can use non-zero streams */ assert(output_var->data.stream == 0 || (output_var->data.stream < MAX_VERTEX_STREAMS && producer->Stage == MESA_SHADER_GEOMETRY)); if (num_tfeedback_decls > 0) { tfeedback_candidate_generator g(mem_ctx, tfeedback_candidates); g.process(output_var); } ir_variable *const input_var = linker::get_matching_input(mem_ctx, output_var, consumer_inputs, consumer_interface_inputs, consumer_inputs_with_locations); /* If a matching input variable was found, add this output (and the * input) to the set. If this is a separable program and there is no * consumer stage, add the output. * * Always add TCS outputs. They are shared by all invocations * within a patch and can be used as shared memory. */ if (input_var || (prog->SeparateShader && consumer == NULL) || producer->Type == GL_TESS_CONTROL_SHADER) { matches.record(output_var, input_var); } /* Only stream 0 outputs can be consumed in the next stage */ if (input_var && output_var->data.stream != 0) { linker_error(prog, "output %s is assigned to stream=%d but " "is linked to an input, which requires stream=0", output_var->name, output_var->data.stream); return false; } } } else { /* If there's no producer stage, then this must be a separable program. * For example, we may have a program that has just a fragment shader. * Later this program will be used with some arbitrary vertex (or * geometry) shader program. This means that locations must be assigned * for all the inputs. */ foreach_in_list(ir_instruction, node, consumer->ir) { ir_variable *const input_var = node->as_variable(); if (input_var == NULL || input_var->data.mode != ir_var_shader_in) continue; matches.record(NULL, input_var); } } for (unsigned i = 0; i < num_tfeedback_decls; ++i) { if (!tfeedback_decls[i].is_varying()) continue; const tfeedback_candidate *matched_candidate = tfeedback_decls[i].find_candidate(prog, tfeedback_candidates); if (matched_candidate == NULL) { hash_table_dtor(tfeedback_candidates); hash_table_dtor(consumer_inputs); hash_table_dtor(consumer_interface_inputs); return false; } if (matched_candidate->toplevel_var->data.is_unmatched_generic_inout) { matched_candidate->toplevel_var->data.is_xfb_only = 1; matches.record(matched_candidate->toplevel_var, NULL); } } const uint64_t reserved_slots = reserved_varying_slot(producer, ir_var_shader_out) | reserved_varying_slot(consumer, ir_var_shader_in); const unsigned slots_used = matches.assign_locations(prog, reserved_slots); matches.store_locations(); for (unsigned i = 0; i < num_tfeedback_decls; ++i) { if (!tfeedback_decls[i].is_varying()) continue; if (!tfeedback_decls[i].assign_location(ctx, prog)) { hash_table_dtor(tfeedback_candidates); hash_table_dtor(consumer_inputs); hash_table_dtor(consumer_interface_inputs); return false; } } hash_table_dtor(tfeedback_candidates); hash_table_dtor(consumer_inputs); hash_table_dtor(consumer_interface_inputs); if (consumer && producer) { foreach_in_list(ir_instruction, node, consumer->ir) { ir_variable *const var = node->as_variable(); if (var && var->data.mode == ir_var_shader_in && var->data.is_unmatched_generic_inout) { if (!prog->IsES && prog->Version <= 120) { /* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec: * * Only those varying variables used (i.e. read) in * the fragment shader executable must be written to * by the vertex shader executable; declaring * superfluous varying variables in a vertex shader is * permissible. * * We interpret this text as meaning that the VS must * write the variable for the FS to read it. See * "glsl1-varying read but not written" in piglit. */ linker_error(prog, "%s shader varying %s not written " "by %s shader\n.", _mesa_shader_stage_to_string(consumer->Stage), var->name, _mesa_shader_stage_to_string(producer->Stage)); } else { linker_warning(prog, "%s shader varying %s not written " "by %s shader\n.", _mesa_shader_stage_to_string(consumer->Stage), var->name, _mesa_shader_stage_to_string(producer->Stage)); } } } /* Now that validation is done its safe to remove unused varyings. As * we have both a producer and consumer its safe to remove unused * varyings even if the program is a SSO because the stages are being * linked together i.e. we have a multi-stage SSO. */ remove_unused_shader_inputs_and_outputs(false, producer, ir_var_shader_out); remove_unused_shader_inputs_and_outputs(false, consumer, ir_var_shader_in); } if (producer) { lower_packed_varyings(mem_ctx, slots_used, ir_var_shader_out, 0, producer, disable_varying_packing, xfb_enabled); } if (consumer) { lower_packed_varyings(mem_ctx, slots_used, ir_var_shader_in, consumer_vertices, consumer, disable_varying_packing, xfb_enabled); } return true; } bool check_against_output_limit(struct gl_context *ctx, struct gl_shader_program *prog, gl_shader *producer) { unsigned output_vectors = 0; foreach_in_list(ir_instruction, node, producer->ir) { ir_variable *const var = node->as_variable(); if (var && var->data.mode == ir_var_shader_out && var_counts_against_varying_limit(producer->Stage, var)) { /* outputs for fragment shader can't be doubles */ output_vectors += var->type->count_attribute_slots(false); } } assert(producer->Stage != MESA_SHADER_FRAGMENT); unsigned max_output_components = ctx->Const.Program[producer->Stage].MaxOutputComponents; const unsigned output_components = output_vectors * 4; if (output_components > max_output_components) { if (ctx->API == API_OPENGLES2 || prog->IsES) linker_error(prog, "%s shader uses too many output vectors " "(%u > %u)\n", _mesa_shader_stage_to_string(producer->Stage), output_vectors, max_output_components / 4); else linker_error(prog, "%s shader uses too many output components " "(%u > %u)\n", _mesa_shader_stage_to_string(producer->Stage), output_components, max_output_components); return false; } return true; } bool check_against_input_limit(struct gl_context *ctx, struct gl_shader_program *prog, gl_shader *consumer) { unsigned input_vectors = 0; foreach_in_list(ir_instruction, node, consumer->ir) { ir_variable *const var = node->as_variable(); if (var && var->data.mode == ir_var_shader_in && var_counts_against_varying_limit(consumer->Stage, var)) { /* vertex inputs aren't varying counted */ input_vectors += var->type->count_attribute_slots(false); } } assert(consumer->Stage != MESA_SHADER_VERTEX); unsigned max_input_components = ctx->Const.Program[consumer->Stage].MaxInputComponents; const unsigned input_components = input_vectors * 4; if (input_components > max_input_components) { if (ctx->API == API_OPENGLES2 || prog->IsES) linker_error(prog, "%s shader uses too many input vectors " "(%u > %u)\n", _mesa_shader_stage_to_string(consumer->Stage), input_vectors, max_input_components / 4); else linker_error(prog, "%s shader uses too many input components " "(%u > %u)\n", _mesa_shader_stage_to_string(consumer->Stage), input_components, max_input_components); return false; } return true; }